In a wireless communication system, a transmitter typically processes (e.g., encodes and symbol maps) traffic data to generate data symbols, which are modulation symbols for data. The transmitter then processes the data symbols to generate a modulated signal and transmits this signal via a wireless channel. The wireless channel distorts the transmitted signal with a channel response and further degrades the signal with noise and interference. A receiver receives the transmitted signal and processes the received signal to obtain data symbol estimates, which are estimates of the transmitted data symbols. The receiver then processes (e.g., demodulates and decodes) the data symbol estimates to obtain decoded data.
The received signal includes noise and interference from the wireless channel as well as noise generated at the receiver, all of which may be collectively referred to as simply “noise”. The noise in the received signal degrades the quality of the data symbol estimates and affects the reliability of the decoded data. The receiver may perform detection and/or decoding in a manner to take into account the noise. A good estimate of the noise may be beneficial for detection and decoding performance.
There is therefore a need in the art for techniques to obtain a good noise estimate in a wireless communication system.